Multi-scale analysis of structures made of triaxially woven fabric composites with stiff and flexible matrix materials

Interest to investigations of mechanical and thermo-elastic properties of triaxially woven fabric composites (TWFC) has been growing in the last years. This process is associated to increasing use of TWFC in large space structures. High precision (large deployable) space antenna reflectors use TWFC more and more often as single shell or sandwich shell reflecting surfaces. To predict the thermo-mechanical behavior of the structures made of TWFC, a multi-scale analysis approach is needed. Performed multi-scale analysis of TWFC structures includes the following levels: fiber matrix micromechanics, classical lamination theory (CLT), micro-mechanical finite element (FE) analysis of a 3D unit cell of the TWFC for derivation of the homogenized material properties in terms of a 9 × 9 [ABD] stiffness matrix, sample size modeling for correlation to tests, and, finally, a FE analysis of a full structure and correlation to tests using the derived homogenized material properties. For the unit cell analysis, a beam FE model has been used. The modeling method permits calculation of mechanical and thermo-elastic properties with the same beam FE model. Analysis results are supported with tests, where correlation is achieved on each scale of the analyses. Obtained results allow concluding that TWFC are transversely (quasi) isotropic materials.